Arduino uses an external power supply.Turn off the computer while connected to USB.In that case, there is an abnormally high current flows from power less frequently.I, ICM7555 using a circuit designed.I wanted to check the operation LTspice use.However, NE555 found.LTspice did not work.I got the following display resistance to change.http://den-nekonoko.blog.so-net.ne.jp/2010-10-07ICM7555 is replaced by the following picture.